1. Field of the Invention
The present invention relates to membranes used in distillation, e.g., for distillation, and particularly to nanocomposite mixed-matrix membrane made from a nanofiller, such as Halloysite nanotubes (HNT) or polypropylene-grafted maleic anhydride-nano-layered silica (Ma-Si), dispersed in a polymer matrix, such as polypropylene (PP).
2. Description of the Related Art
Despite great success and potential of the current membrane technology for water desalination, including great improvements in water quality and an increase in recovery factor of the desalination processes, there are several potential pitfalls. These problems include both bio-fouling and inorganic fouling, high energy consumption, huge costs, and high brine disposal that may lead to serious environmental impact. There are also other potential problems associated with high-pressure driven membranes (i.e., NF, UF, MF and RO) that include membrane compaction caused by the use of high pressure that leads to shorter service life; limitation of reverse osmosis (RO) membranes to low salinity of about 5% or less; low recovery factor of 40-60%; and others. In addition to these membrane-associated problems, there are other problems that include the 21st century global challenges. These challenges include water stress, climate change, environmental issues, and energy crisis. This has prompted investigations for new and innovative solutions. The two major areas of research in this context have been directed towards the development of an effective membrane distillation (MD) membrane with improved vapor flux and improved mechanical, physical and morphological properties, and towards the use of integrated membrane systems, including MD membranes.
Although membrane distillation (MD) has been known for the past four decades, its use in water desalination has gained wide attention worldwide, and lots of intensive research has been carried out during the last ten years. Membrane Distillation is an emerging non-isothermal separation technique that uses a microporous hydrophobic membrane in contact with an aqueous heated solution on one side (feed or retentate), and a condensing phase (permeate or distillate) on the other side. It is thought that nanotechnology can be used with polymers in MD membranes to improve their properties.
Thus, a nanocomposite mixed-matrix membrane solving the aforementioned problems is desired.